1. Field of the Invention
The present invention relates to a charge-coupled device type solid state imaging device (hereinafter, referred to as CCD solid state imaging device) for use in a video camera or the like.
2. Description of the Prior Art
CCD solid state imaging devices are purposed principally for outputting an image onto a television screen, where its aspect ratio, number of pixels, and the like are determined according to the television format. The aspect ratio refers to the ratio of a screen's horizontal dimension to vertical dimension.
In recent years, other than the aspect ratio of 4 : 3 that has been adopted in conventional television systems, there have been marketed televisions of wide aspect ratios of 16 : 9 and others that are horizontally widened than before. In correspondence to this, there have also been commercially available camera-integrated VTRs (Video Tape Recorders) that allow images of both aspect ratios of 4 : 3 and 16 : 9 to be obtained.
The solid state imaging device contained in the aforementioned camera-integrated VTRs is either one in which top and bottom parts of an image by the image sensor of the 4 : 3 aspect ratio are cut off by digital processing into an image of the 16 : 9 aspect ratio, or another in which a conversion lens is fitted in front of the lens to thereby optically compress the image into a 16 : 9 aspect ratio image.
Further, as the above CCD solid state imaging device, there has been proposed a solid state imaging device in which an image is horizontally cut off by digital processing or the like to result in a 4 : 3 aspect ratio image with the use of a solid state image sensor corresponding to the aspect ratio of 16 : 9.
However, in the CCD solid state imaging device in which top and bottom parts of an image by the solid state image sensor of a 4 : 3 aspect ratio is cut off, there is a problem that the vertical resolution would be deteriorated.
Further, in the CCD solid state imaging device in which right and left parts of a 16 : 9 aspect ratio image are cut off, the horizontal resolution for a 16 : 9 aspect ratio image could be ensured enough, compared with the case where an image by a solid state image sensor of a 4 : 3 aspect ratio is expanded right and left to obtain a 16 : 9 aspect ratio. But this would result in less use of effective pixels to obtain a 4 : 3 aspect ratio image, disadvantageously.
In this case, also, since the cutoff of an image and expansion of a time axis are necessarily performed by digital signal processing, the CCD solid state imaging device would become expensive, as another problem.
As still another problem, a CCD solid state imaging device using a conversion lens would not only involve increase in optical parts also but require troublesome operation.